In recent years, attention has been given to a hybrid vehicle as an environmentally-friendly vehicle which runs utilizing the driving force generated by an internal combustion engine representative of an engine and the driving force from a rotating electric machine driven with the electric power stored in a vehicle-mounted power storage device (for example, a secondary battery, a capacitor and the like).
Also known is a self-diagnosis function (also hereinafter referred to as an OBD “On Board Diagnosis”) that can automatically detect malfunctions in the engine during driving of the engine, thereby allowing the user to readily grasp the causes and the like of failures. In a hybrid vehicle, the engine is stopped when the vehicle runs only with the driving force from the rotating electric machine or when the vehicle is not running. Accordingly, it is conceivable that the frequency of performing malfunction detection by this OBD is decreased as compared with the vehicle driven only by the engine.
Japanese Patent Laying-Open No. 2010-052610 (PTL 1) discloses the configuration in which the engine state during the previous engine operation is stored, and when it is highly likely that a malfunction has occurred in the engine, the engine start determination value is lowered. According to the configuration disclosed in Japanese Patent Laying-Open No. 2010-052610 (PTL 1), when it is highly likely that a malfunction has occurred in the engine in light of the stored engine state during the previous engine operation, the engine can be started at an earlier stage than usual. Accordingly, it can be detected at an early stage whether the engine malfunction continues or not, and also, the user can be notified of the malfunction of the engine.